Technophile: Extra voltage

We test drive three iPhone rechargable battery cases to find which gives the most app-time for the buck.

Mophie Juice Pack Air for iPhone 4 charger. Photo courtesy Mophie
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Dexim DCA224 Super-Juiced Power Case

The specs The Dexim DCA224 comes with a mini USB port and cable. The case promises six extra hours of talk time, 10 more hours of video playback and an impressive 40 additional hours of audio playback, so you shouldn't have to take your earbuds out until after your transcontinental flight lands (and perhaps not even for your entire trip, if you prefer).

The look This slim case comes with a hinge in the back that locks the iPhone securely into position, but has a bit of trouble letting go when it needs to be removed. Also in the back is a kickstand, which allows the iPhone to be propped up and viewed hands-free.

Power move Though not as popular as the Mophie Juice Pack case, the Dexim performs just as well and the kickstand makes it the perfect mobile charger for travellers who like to sit back and watch movies or TV shows while on the go.


Mooncharge Hybrid Solar Battery Case

The specs Though not the most aesthetically pleasing iPhone charger case, the Mooncharge Hybrid is one of the few that can draw power from the sun as well as a USB. When fully charged, the case adds about five hours of talk time, 10 hours of video and 27 hours of audio playback. Its makers claim you will get an extra five minutes of talk time for every 20 minutes it is left in direct sunlight.

The look The Mooncharge Hybrid covers the back bottom and sides of the phone, leaving the front and top exposed, which could leave your magic phone vulnerable to a concussion should you drop it on its head.

Power move There are not many green solutions when it comes to portable smartphone chargers, and the Mooncharge Hybrid offers convenient compromises. Obviously, it charges up faster via USB, but it can also "top off" an iPhone's battery by soaking up the sun's rays when out in the wild blue yonder. However, you must be willing to be seen with a case that, from the back, looks like the grille of a Mack truck.


Mophie Juice Pack Air

The specs The slick, tight-hugging Juice Pack offers the iPhone not just a protective case, but also adds up to six hours of talk time, nine hours of video and 36 hours of audio playback.

The look The Juice Pack covers all sides of the iPhone except the screen and hides its battery in a rubber-curved bulge on the backside. An LED power-use indicator rests at the bottom of the case. It comes with a mini USB port and cable, which allows you to recharge the case in the battery and the battery in your iPhone all at the same time.

Power move Widely considered the best bet in the niche portable iPhone charger market, the Juice Pack comes with many welcome touches, including a power switch that allows you to conserve juice until you need it and a design that redirects audio from the iPhone's bottom speakers to flow out from the front of the device. It is a bit bulky, but power users will probably be able to live with the added heft.